John Gruber’s post on DaringFireball about the Griffin PowerMate reminded me that I still own one. I had more or less given up on it after Griffin stopped supporting newer versions of macOS, but his write-up got me curious again.
Unfortunately, the repository Gruber linked to targets the original USB version of the PowerMate, while mine is the Bluetooth LE model. That distinction turned out to matter quite a bit.
That ended up being the motivation to build a driver specifically for the BLE version. I did find an older Objective-C implementation (credited in my repository README), which served as a useful reference, but I’ve since rebuilt it in modern Swift 5.9 with the required entitlements and macOS support.